COMPLEXES OF 2-METHOXYBENZYLIDENEPYRUVATE WITH SOME BIVALENT METAL IONS
2
C. B. Melios, J. T. S. Campos, M. A. C. Mazzeu,
L. L. Campos, M. Molina and J. O. Tognolli,
Inorg. Chim. Acta, 139 (1987) 163.
C. B. Melios, H. Redigolo and M. Molina, J. Inorg. Biochem.,
36 (1989) 307.
C. B. Melios, M. Ionashiro, H. Redigolo, M. H. Miyano
and M. Molina, Eur. J. Solid State Inorg. Chem.,
28 (1991) 291.
thermic peaks at 430°C (Mn); 200 and 415°C (Fe);
15°C (Co); 410°C (Ni); 200, 270 and 500°C (Cu); 300
4
and 490°C (Zn) are attributed to the oxidation of organic
matter. Calculations based on the mass losses up to the
final temperature of thermal decomposition are in agree-
ment with the formation of the respective oxides:
Mn O , Fe O , Co O , NiO, CuO and ZnO. These ox-
3
4
3
4
2
3
3
4
5
6
R. N. Marques, M. Molina and M. Ionashiro,
J. Alloys Compd., 249 (1997) 102.
L. C. S. de Oliveira, C. B. Mélios, C. A. Ribeiro,
M. S. Crespi and M. Ionashiro, Thermochim. Acta,
ides were confirmed by X-ray powder diffraction pat-
terns. For the cobalt compound the mass loss that occurs
between 885 and 920°C, corresponding to the endother-
mic peak at 895°C is due to the reduction of Co
O to
3 4
219 (1993) 215.
CoO and in agreement with the literature [14, 26].
7
8
9
M. H. Miyano, C. B. Mélios, C. A. Ribeiro, H. Redigolo
and M. Ionashiro, Thermochim. Acta, 221 (1993) 53.
D. E. Rasera, L. S. C. Oliveira, C. B. Mélios and
M. Ionashiro, Thermochim. Acta, 250 (1995) 151.
N. S. Fernandes, M. A. S. Carvalho Filho, C. B. Mélios
and M. Ionashiro, J. Therm. Anal. Cal., 59 (2000) 663.
The mass losses, temperature ranges and the
peak temperatures observed in each step of the
TG-DTA curves are shown Table 3.
The DSC curves of the compounds are shown in
Fig. 2. These curves show endothermic and exother-
mic peaks in agreement with mass losses observed in
the TG curves. For iron, nickel and copper com-
pounds no endothermic peak is observed in the DSC
curves due to the dehydration, in disagreement with
the TG-DTA curves. This disagreement probably
must to be dehydration of these compounds in the
desiccator over anhydrous calcium chloride, because
the DSC curves were obtained six month after the
TG-DTA curves.
10 R. N. Marques, C. B. Mélios and M. Ionashiro,
J. Alloys Compd., 344 (2002) 88.
11 G. Bannach, E. Schnitzler and M. Ionashiro, Ecl. Quim.,
28 (2003) 145.
2 R. N. Marques, C. B. Mélios and M. Ionashiro,
Thermochim. Acta, 395 (2003) 145.
3 N. S. Fernandes, M. A. S. Carvalho Filho, C. B. Mélios
and M. Ionashiro, J. Therm. Anal. Cal., 73 (2003) 307.
4 I. A. Petroni, F. L. Fertonani, C. B. Mélios and
M. Ionashiro, Thermochim. Acta, 400 (2003) 187.
15 N. S. Fernandes, M. A. S. Carvalho Filho, R. A. Mendes,
C. B. Mélios and M. Ionashiro, J. Therm. Anal. Cal.,
1
1
1
The endothermic peak at 130°C (Mn, Co),
20°C (Zn) is assigned to the dehydration. The exo-
76 (2004) 193.
1
1
1
6 G. Bannach, E. Schnitzler, C. B. Mélios and M. Ionashiro,
Ecl. Quim., 29 (2004) 31.
7 G. Bannach, R. A. Mendes, E. Y. Ionashiro, A. E. Mauro,
E. Schnitzler and M. Ionashiro, J. Therm. Anal. Cal.,
79 (2005) 329.
thermic peak 200°C (Fe) and 180°C (Cu), probably is
due to the elimination of methoxy group, and the exo-
thermic peaks or exotherm are attributed to the oxida-
tion of the organic matter.
18 E. Y. Ionashiro, F. L. Fertonani, C. B. Mélios and
M. Ionashiro, J. Therm. Anal. Cal., 79 (2005) 299.
Conclusions
19 R. A. Mendes, G. Bannach, E. Y. Ionashiro and
M. Ionashiro, Ecl. Quim., 30 (2005) 299.
20 M. Reimer and M. Howard, J. Am. Chem. Soc.,
From TG and complexometry data, a general formula
can be established for the synthesized compounds. The
X-ray powder diffraction patterns pointed out that the
manganese and cobalt compounds have a crystalline
structure while the other compounds were amorphous.
Infrared spectroscopic data suggest that 2-MeO-BP acts
as a bidentate ligand towards the metal ions considered
in this work. The TG-DTA and DSC curves provided
previously unreported information on the thermal stabil-
ity and thermal decomposition of these compounds.
50 (1928) 2506.
th
1 H. A. Flaschka. EDTA Titrations. 2 Ed., Pergamon Press,
2
2
2
New York 1964.
2 G. Socrates, Infrared Characteristics Group Frequencies,
nd
2
Ed., Wiley, New York 1994, pp. 91, 236.
3 R. M. Silverstein and F. X. Webster, Spectrometric
th
Identification of Organic Compounds, 6 Ed., Wiley,
New York 1998, pp. 92–93, 96–97.
2
4 F. A. Cotton, J. Lewis and R. G. Wilkius, Eds,
The Infrared Spectra of Transition Metal Complexes in
Modern Coordination Chemistry, Interscience,
New York 1960, pp. 379–386.
25 K. Nakamoto, Infrared and Raman Spectra of Inorganic
th
and Coordination Compounds, Part B, 5 Ed., Wiley,
Acknowledgements
New York 1997, pp. 58–61.
6 Z. P. Xu and H. C. Zeng, J. Mater. Chem., 8 (1998) 2499.
The authors thank FAPESP (Proc. 97/12646-8), CAPES and
CNPQ Foundations (Brazil) for financial support.
2
Received: April 12, 2007
Accepted: July 12, 2007
References
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